Secrets of the Darkest Art
by Khaemera
Summary: AU: Since Harry returned from the cave with the fake Horcrux Regulus left behind, Tonks' younger sister, Ariana, has grown fond of the piece of jewelry and what it represents. But what if the necklace Regulus replaced Slytherin's locket with was also a Horcrux? What if Regulus is not what he seems?
1. Chapter 1

**This story starts off with a rather long quote from OoTP- I've italicized it to clarify where JK's lovely work ends and my attempt to recapture her fantastic world begins. The quote and the opening scene actually take place in OoTP, but Harry and Dumbledore have already retrieved the locket from the cave. You'll see why. It becomes AU rather quickly, anyway. ;-) Please review and tell me what you think so far!**

_The tapestry looked immensely old; it was faded and looked as though doxies had gnawed it in places; nevertheless, the golden thread with which it was embroidered still glinted brightly enough to show them a sprawling family tree dating back (as far as Harry could tell) to the Middle Ages. Large words at the very top of the tapestry read:_

_**T**__**HE**__** N**__**OBLE**__** A**__**ND**__** M**__**OST**__** A**__**NCIENT**__** H**__**OUSE**__**OF**__** B**__**LACK**__**  
"T**__**OUJOURS**__** P**__**UR**__**"**_

…_Sirius jabbed a finger at the very bottom of the tree, at the name __**REGULUS BLACK**__. A date of death (some fifteen years previously) followed the date of birth._

_"He was younger than me," said Sirius, "and a much better son, as I was constantly reminded."_

_"But he died," said Harry._

_"Yeah," said Sirius. "Stupid idiot…he joined the Death Eaters."…_

_"Was he killed by an Auror?" Harry asked tentatively._

_"Oh, no," said Sirius. "No, he was murdered by Voldemort. Or on Voldemort's orders, more likely, I doubt Regulus was ever important enough to be killed by Voldemort in person. From what I found out after he died, he got in so far, then panicked about what he was being asked to do and tried to back out. Well, you don't just hand in your resignation to Voldemort. It's a lifetime of service or death."…_

_"I haven't looked at this for years. There's Phineas Nigellus…my great-great-grandfather, see? Least popular Headmaster Hogwarts ever had…and Araminta Meliflua…cousin of my mother's…tried to force through a Ministry Bill to make Muggle-hunting legal…of course, anytime the family produced someone halfway decent they were disowned. I see Tonks isn't on here. Maybe that's why Kreacher won't take orders from her- he's supposed to do whatever anyone in the family asks him…"_

_-Harry Potter and the Order of the Phoenix, pg.111-112_

…and her sister- my other cousin- she's missing, too-"

"You mean me, of course." Harry and his godfather turned to see a young woman, about twenty-one years old, with glossy black hair and grey eyes that matched Sirius'. She was leaning against the doorframe of the drawing room with a smirk identical to the one that was spreading across Sirius' aristocratic features.

"Ariana," Sirius said finally. "I take it Tonks brought you?"

The woman winked. "You bet. Have you ever known me to miss out on a chance to get involved in something delightfully sneaky?" She wrinkled her nose at Harry. "Wotcher," she said simply. "You must be Harry."

Harry nodded. "Yes, er-"

"Don't worry," she assured him. "I'm not nearly as clumsy as my big sister. And, unfortunately, I missed out on the Metamorphmagus boat. But I'm much cooler than she is."

Harry stifled a laugh. "Nice to meet you."

She laughed. "I was at Hogwarts with you." At his blank look, she shrugged. "I was a fifth year when you were in first. Ravenclaw. You probably don't remember me."

Harry shook his head. "Sorry," he said regretfully.

"Have you eaten?" Sirius interrupted, remembering his manners. "Molly's making sandwiches, I believe."

Ariana's face brightened. "Cool. I'm starving." She followed them into the kitchen, seating herself at the long oak table and accepting a sandwich from Mrs. Weasley. When Sirius quirked an eyebrow at her in an unspoken question, she laughed. "Yes, I'm staying for the Meeting. When is it?"

"Any minute now," Mrs. Weasley interrupted. "I'd hurry up and eat that, if I were you."

Ariana tossed her long, black hair over her shoulder and bit into her sandwich. "Thank you, Molly," she said politely, after swallowing and wiping her mouth daintily with the corner of a napkin.

Sirius chuckled. "At least one of the Tonks sisters learned her manners."

"I heard that," Nymphadora Tonks said reprovingly, walking by and tweaking her cousin's ear. She beamed at Harry. "Wotcher, Harry."

"Hey, Tonks," he said. "Do I get to stay for the Meeting?"

"You most certainly do not," Mrs. Weasley replied before Sirius could get a word in. She turned her head to the door when Sirius' mother's shrieks filled the hallway. "That'll be Albus now." She waved a wooden spoon at him threateningly. "Shoo."

Harry stood obediently, trying not to let Mrs. Weasley see how upset he was. How could they not include him? He was fifteen; not to mention, he had fought Voldemort himself back in June! He glanced over at Ariana, who was working on her sandwich. She was studiously ignoring him, and he frowned. Sirius wasn't even going to stand up for him! He stormed out of the room, narrowly avoiding running into Professors Dumbledore and Snape in the doorway. "Hullo," he muttered, and vanished up the stairs.

* * *

_As he replaced his wand in his pocket, Harry saw that his hand was black and shriveled; it looked as though his flesh had been burned away._

_"Sir- what happened to your-?"_

_"Later, Harry," said Dumbledore . "Please sit down."_

_-Harry Potter and the Half-Blood Prince, pg. 49_

Night had fallen, and Ariana was struggling to stay awake as the room darkened. Her sister kept kicking her in the shins underneath the table, but she hoped for propriety's sake that the meeting was almost over. Even Sirius looked dazed, head resting in his hand as Dumbledore spoke to the assembled Order.

"As for the next order of business-" Dumbledore suddenly reached into the pocket of his robes and brandished a locket in the air with his fist. Its golden chain flashed in the light of the sputtering candles. Ariana sat up, interested. Beside her, she felt Sirius lift his head. "I am sure that by now all of you have heard the story of how Regulus Black sacrificed himself to defeat Voldemort. As Harry will tell you, this is, in fact, the very locket that young Mr. Black left behind that day many years ago. If so, by rights, it belongs to Regulus' only surviving family. Sirius?"

Her cousin had gone a strange shade of green and was eyeing the locket cautiously. "That's the locket Reg left in the basin?" he croaked.

Dumbledore fixed him with a look over the top of his half-moon glasses. "Indeed, it is, Sirius." He stretched out his hand across the long oak table. "It is yours now."

Sirius shook his head. "That was my mother's," he said indignantly. "It's probably cursed. You should destroy it."

Dumbledore raised an eyebrow, but said nothing.

Ariana rolled her eyes. "Oh, for goodness sake, Sirius!" She stood and accepted the locket from the Headmaster. Turning to the Animagus, she scolded, "This is a treasure- an artifact. It should be kept safe so that our children and our children's children can know that what Regulus did was real- and it was for all of us."

Dumbledore's eyes twinkled. "Well said," he agreed. "I trust you are capable of this task, Miss Tonks?"

Ariana nodded, distracted. "Of course." She returned to her seat, turning the piece of jewelry over in her hand. It gave off a strange heat; she was surprised that Dumbledore hadn't noticed. She stole a glance at his blackened right hand. Perhaps it _was_ cursed. Beside her, Sirius frowned. "Better toss that," he advised in an undertone. "Who knows what Dark Magic Reg used on it."

Ariana made a face at him. "He was your brother," she reminded him, as Dumbledore began discussing something to do with goblins. "Quit being such an old grump."

Sirius frowned. "I'm only looking out for you," he pointed out gruffly. "Get rid of it."

"You're not my father," she snapped, feeling tired and childish.

Sirius' eyes narrowed. "Fine," he said curtly, standing up and walking out of the kitchen.

Ariana met her sister's eyes across the table. "What did you do?" Tonks mouthed. Ariana rolled her eyes and turned back to Dumbledore. Let Sirius sulk- he'd always been moody.


	2. Chapter 2

**I've decided to continue using small quotes from throughout the series in each chapter. Mind you, the story is already AU, but I try to keep things as authentic as I can, where possible. Hope you enjoy!**

_He turned the locket over in his hands. This was neither as large as the locket he remembered seeing in the Pensieve, nor were there any markings on it, no sign of the ornate S that was supposed to be Slytherin's mark. Moreover, there was nothing inside but for a scrap of folded parchment wedged tightly into the place where a portrait should have been._

_Automatically, without really thinking about what he was doing, Harry pulled out the fragment of parchment, opened it, and read by the light of the many wands that had now been lit behind him:_

_**To the Dark Lord,**_

_**I know I will be dead long before you read this**_

_**But I want you to know that it was I who discovered your secret.**_

_**I have stolen the real Horcrux and intend to destroy it as soon as I can.**_

_**I face death in the hope that when you meet your match,**_

_**You will be mortal once more.**_

_**R.A.B.**_

-_Harry Potter and the Half-Blood Prince, pg. 609_

That night, Ariana lay sprawled on her stomach across her bed, turning the golden locket over in her hand. It glinted in the light from the solitary candle left on her nightstand; her older sister snored from her position under the quilts in her own bed under the window. The locket felt warm and heavy in Ariana's palm. She frowned and pried it open- there was nothing inside. Harry had removed the note Regulus had left within. Ariana suddenly felt a strong desire to see her cousin's small, cramped writing once again. She had been only four years old when Reg died- she had only the vaguest of memories of a tall, black haired boy, smaller, slighter, and less handsome than his older brother, Sirius.

Playing with the long, golden chain, Ariana suddenly felt a surge of anger and another emotion- one oddly like fear. She dropped the locket, astonished. When she scooped it back up from the bedspread, the necklace throbbed in her palm, its slow, even pulse resembling a heartbeat. She frowned. Maybe Sirius was right- maybe it was cursed. Reacting to a strong impulse she couldn't identify, she slipped the chain over her head, comforted by the locket's- surely it couldn't be a heartbeat?- pulsations. She curled up on her side and closed her eyes, sinking easily into sleep.

* * *

Ariana was awoken just before dawn, her heart pounding to a rhythm matching the one that reverberated through the locket she wore around her neck. She clutched the golden chain as she sat straight up in bed, running her other hand through her glossy black hair and replaying her dream in her mind. It had been more of a memory than a dream, she remembered that. She had been barely four years old, standing in the doorway of her family's small sitting room, hidden by the flickering shadows thrown along the walls by the fire in the grate. Her mother and Sirius were sitting on the couch, speaking earnestly to a young, dark-haired man- her cousin, Reg- who was furious to the point that tears were streaming down his face.

_"Reg, can't you see what monsters those people are?" Sirius had shouted. His hands were clenched into fists beside him._

_"It doesn't matter!" Regulus had yelled back. "I can't get away, Sirius. You know that! I'm all Mum and Dad have left!"_

_"So it's my fault, is it?" Sirius had stated sourly. Ariana's mother had reached over and patted his arm gently, but he wrenched it away. "It's easy to blame me, isn't it? Be honest, you buy into all that Pureblooded insanity!"_

_"I do not!" Regulus had gone white. "Sirius, I came here because I thought maybe you and Cousin Andromeda could help me. But he'll find me, wherever I go. I can't hide from him! And Bella- Sirius, you know what she'll do to me!"_

_Ariana's mother had paled, too, her beautiful features stark in the firelight. "Regulus, you know your brother and I will do everything in our power to help you. But you have to understand-"_

_Regulus had shaken his head. "I'll have to find some other way," he stated flatly. "I would just put both of you in danger. And what about your children, cousin?" He had paused before running a hand through the black hair that all of the Blacks shared. "I don't know what I was thinking, coming here," he said finally, defeated. "Goodbye, Sirius. Cousin." _

_Ariana had scampered up the stairs to the landing in the shadows before he had reached the door. As his hand alighted on the handle, however, he had half turned and whispered, "Go to bed, little one. This doesn't concern you. Everything is alright."_

_And he had left._

Ariana sighed and glanced at the sun peeking through the curtains. Her sister was still asleep, peacefully dreaming. Ariana rose and slipped on her robes before tiptoeing down the stairs to the kitchen. The house was still and quiet, its occupants still sleeping. She shuddered as she passed the house elves' heads mounted on the wall in the hallway. How had her cousins managed to live in a place like this?

As she entered the kitchen, she saw that at least one other person had been able to sleep, as well. Sirius was sitting at the table, a half-empty bottle of Firewhiskey in front of him. He was wearing the same clothes from yesterday, and he smelled like stale drink. She entered cautiously. "Hello, Sirius."

Sirius looked up, and his eyes were rimmed with shadows. "You're up early," he said gruffly.

"I had a nightmare," she said simply.

He nodded. "I know what those are like." He gestured to the Firewhiskey. "Want a drink?"

She shook her head. "Sirius, it's almost dawn. If Molly catches you with that-"

He grunted and took a long swig. "Dawn, you say? Good. I'm ready for the sun to come up."

Ariana eyed him critically. Her memories of him before his trip to Azkaban were few, and vague at that. But the wizard prison had seemed to add an edginess to his character that she didn't remember. Sirius had always been rash and impulsive- when they were younger, her mother had used to warn her and Nymphadora not to act like their cousin. He was thinner, and markedly less handsome than he had been in his youth.

Sirius felt her eyes on him and frowned. "What?"

"Nothing," she said quickly. "I'm just trying to remember what you were like before- you know…"

"Azkaban," he said simply. "You can say it. Dementors won't come swooping down on you or anything." He paused, his eyes narrowing. "Are you _wearing_ that old thing?" He pointed to the locket that hung on its golden chain around her neck. "Ana, I'm telling you, it belongs in Borgin & Burkes. It was probably Mother's."

"It is not," she said defensively, wrapping her hand around it and feeling the steady beat of it underneath her fingers.

"Do you even remember Reg?" Sirius asked suddenly. "You were still quite young when- anyway." He looked away, and Ariana realized he was ashamed of his brother's fate.

"Are you angry at him?" she asked.

Sirius head snapped up. "Of course I am!" he said fiercely. "He didn't have to end up like he did- your mother would have done anything he asked to help him get away from those maniacs. Hell, _I_ would have-" He paused. "He was too soft," he said finally. "He bought into all of it."

"No, he didn't." Ariana said defensively. "He just knew he couldn't get out."

Sirius' eyes narrowed again. "How do you know that?"

She raised an eyebrow. "Kreacher told us what happened in the cave. Regulus sacrificed himself to destroy You-Know-Who's Horcrux."

Sirius snorted. "Reg wouldn't know a Horcrux if it hit him in the head," he said dismissively. "And Kreacher's mad as an old bat. He lived here with Mother's portrait for all those years, you know."

Ariana frowned. "Really? You don't believe any of it?"

"Not a word." Sirius pointed an accusatory finger at the locket. "Kreacher probably stole that from Mother's old jewelry box."

Ariana opened her mouth to retort, but at that exact moment, Mrs. Weasley breezed into the kitchen. "Good morning, Ariana," she said kindly. She paused for a moment before saying, "Hello, Sirius."

"Molly," Sirius acknowledged grudgingly. The relationship between the Black heir and the Weasley family matron was decidedly frosty.

Sensing the tension in the room, Ariana rose to her feet, making her excuses before slipping off to go upstairs. She paused by the door to the room that Harry and Ron were sharing. There were voices from within- one of them a female's. Feeling guilty, Ariana leaned in to listen.

* * *

_"…my point is that whatever happens to your body, your soul will survive, untouched," said Hermione. "It's the other way around with a Horcrux. The fragment of soul inside it depends on its container, its enchanted body, for survival. It can't exist without it."_

_..."Hang on," said Ron, frowning. "The bit of soul in that diary was possessing Ginny, wasn't it? How does that work, then?"_

_"While the magical container is still intact, the bit of soul inside it can flit in and out of someone if they get to close to the object. I don't mean holding it for too long, it's nothing to do with touching it," she added before Ron could speak. "I mean close emotionally. Ginny poured her heart out into that diary, she made herself incredibly vulnerable. You're in trouble if you get too fond of or dependent on the Horcrux."_

_-Harry Potter and the Deathly Hallows, pg. 104-5_

Harry frowned. "I wonder how Dumbledore destroyed the ring? Why-?" He paused, frowning at the bedroom door. He had heard a floorboard creak. He caught Ron's eye, who simply shrugged. Summoning his courage, he called out boldly, "Who's there?"

A muffled voice answered. "It's me, Ariana. Molly's taken over the kitchen, so I thought I'd see what you three are up to. May I come in?"

Harry rose and opened the door. Ariana was leaning over, clutching the locket she wore around her neck. As the door swung open, she straightened, her arm falling to her side as she regained the haughtily arrogant look common to all Blacks. "Wotcher, Harry," she said cheerfully. "Sorry to bother you. What are you three doing?"

Harry was eyeing the necklace around her throat. "Is that- ?"

"That's Regulus' locket!" Hermione said indignantly behind him. "What are you doing with that?"

Ariana frowned. "Sirius gave it to me. It belongs to the Black family."

"Sirius is the heir, not you," Harry pointed out. "Why didn't he give it to Tonks? Besides, you were too young to remember Regulus, weren't you?"

She raised a black eyebrow. "For your information, I do remember my cousin, thank you very much." Deciding the best defense was a good offense, she asked sharply, "And how do you all know so much about Horcruxes, anyway?"

"You were listening?" Ron sputtered angrily.

Ariana shrugged. "This is my family's house."

"Your family was disowned," Hermione said sharply. "You're not the heir of anything. And you don't see Sirius sticking his nose in everyone else's business."

Ariana straightened up taller. "Sirius is too busy sticking his nose in a bottle of Firewhiskey right now, if you must know."

"Hey!" Harry said angrily. "He's my godfather!"

The young woman tossed her glossy black hair over her shoulder. "I can see this is going nowhere," she said haughtily. "I'll just head to my room, then." And she turned and left.


End file.
